Phenotypic expression of different efflux systems to antiseptics in coagulase negative Staphylococci

JORGE CORREA; M AGUSTINA AZPIROZ; SILVIA PREDARI; DE PAULIS A; CECILIA QUIROGA; DANIEL SORDELLI; PAOLA JERIC

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2007

Health care associated infections constitute one of the greatest challenges of modern medicine. Antiseptics, one of the first barriers, prevent the spread of skin pathogens. A phenotypic and molecular analysis of efflux systems to ethidium bromide, sodium dodecyl sulfate (SDS), sodium deoxycholate, and benzalkonium chloride was performed in 39 coagulase-negative staphylococci isolates. The Minimum Inhibitory Concentration (MIC) in presence/absence of m-chlorophenylhidrazone (CCCP) was performed using Staphylococcus (S.) aureus ATCC 29213 and an Escherichia coli MG1655 mutant (AcrAB/TolC overexpression). The presence of the genes and was determined by PCR and the clonal dispersion was analyzed by PFGE. Of the 39 isolates, 12 S. epidermidis (30.8%) and 22 S. haemolyticus (56.4%) showed efflux to ethidium bromide, 11 S. epidermidis (28.2%) and 21 S. haemolyticus (53.8%) to SDS. All the S. haemolythicus (56.4%) and 11 S. epidermidis (28.2%) extruded sodium deoxycholate. Only 7 S. epidermidisand 17 S. haemolyticus expulsed benzalkonium chloride. The gene qacA/B was found in only 3 S. epidermidis and in 5 S. haemolythicus whereas was found in all of them. The results show a wide diversity in the phenotypic expression of resistance to antiseptics, which would indicate various pumps present in a strain. The mechanism of efflux to antiseptics is polyclonal since great variety was found in the two species